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Original Research—Laryngology and Neurolaryngology

Alterations in Extracellular Matrix

Composition in the Aging Larynx

Otolaryngology–

Head and Neck Surgery

2015, Vol. 152(2) 302–307

American Academy of

Otolaryngology—Head and Neck

Surgery Foundation 2014

Reprints and permission:

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DOI: 10.1177/0194599814562727

http://otojournal.org

Anete Branco, SLP, PhD

, Alexandre Todorovic Fabro, MD, PhD

Tatiana Maria Gonc

alves, MD

, and

Regina Helena Garcia Martins, MD, PhD

Sponsorships or competing interests that may be relevant to content are dis-

closed at the end of this article.

Abstract

Objective.

To study by immunohistochemistry the alterations

of collagens I, III, IV, and V and elastin in the aging process of

the human larynx.

Study Design.

Cadaver study.

Setting.

Universidade Estadual Paulista, Botucatu Medical

School, Sa˜o Paulo State University (UNESP), Brazil.

Subjects and Methods.

Thirty vocal folds were obtained at

autopsy from 10 adult men (aged 30 to 50 years) and 20

geriatric men (10 aged 60 to 75 years and 10 aged

years). Mid membranous vocal fold slides were subjected to

immunohistochemical reactions. Digital imaging software

(ImageJ) was used to quantify the increase in brownish stain-

ing of the lamina propria structures of vocal folds, from

superficial to deep layers.

Results.

There was an increase of collagen I and III immu-

noexpression in the elderly larynges, in both layers.

Collagens IV and V were immunoexpressed in the vessels

endothelium of the lamina propria and in the basement

membrane. The immunoexpression of elastin decreased in

the elderly larynges, in both lamina propria layers of the

vocal folds.

Conclusion.

A clear increase of collagens I and III and a

decrease of elastic fibers were observed in the lamina pro-

pria of vocal folds. The concentration of collagens IV and V

was the same across age groups. These findings suggest that

as men age, the density of the extracellular matrix increases,

brought about by an increase in collagen, while the loss of

elastin results in decreased viscoelasticity.

Keywords

collagen, elastin, aged, lamina propria, vocal folds, larynx,

immunohistochemistry

Received May 15, 2014; revised October 28, 2014; accepted

November 14, 2014.

he physiology of voice production is intimately con-

nected with the characteristics of the vocal fold lamina

propria,

1,2

the vocal fold being the main vibrating

structure during phonation.

In the pursuit to understand the

vocal properties typical of age groups, sexes, and diseases,

researchers have gone deeper in their morphological studies,

trying to elucidate the mechanisms involving the lamina pro-

pria microstructures of vocal folds, mainly relating to elastic,

collagen, and protein fibers.

Collagen fibers are found across the whole lamina pro-

pria, from its superficial to its deepest layers,

4,5

supporting

tissue structure through enhanced stability and resistance,

relevant to vocal physiology. Gray et al

confirmed that col-

lagen and elastic fibers are involved in vocal fold biomecha-

nics, in which the former allow tension and stretching while

the latter allow deformation and a quick return to the initial

shape.

The composition of the vocal folds extracellular matrix

varies significantly between sexes and age groups, implying

biomechanical differences that directly influence the vocal

properties.

The lamina propria trilaminar structure in the

adult larynx described by Hirano

is not present in the new-

born.

3,9,10

It starts to organize only in childhood, from 6

years of age onward. In aging people, anatomical and func-

tional changes occur in the vocal tract, especially in the

vocal folds. At this stage of life, structural and functional

changes take place in the epithelial covering, the muscle,

and the lamina propria of vocal folds, notably, the atrophy

of epithelial layers and the vocal muscle, as well as density

alterations in collagen and elastic fibers and in hyaluronic

acid.

11-13

Elastic fibers change morphologically in elderly people,

relative to adults. Their remodeling with age is reflected by

Ophthalmology, Otorhinolaryngology, Head and Neck Surgery Depart-

ment, Botucatu Medical School, UNESP–Univ Estadual Paulista, Sa˜o Paulo,

Brazil

Department of Pathology, Botucatu Medical School, UNESP–Univ Estadual

Paulista, Sa˜o Paulo, Brazil

Corresponding Author:

Regina Helena Garcia Martins, SLP, PhD, Botucatu Medical School/UNESP,

Ophthalmology, Otorhinolaryngology, Head and Neck Surgery Department,

Distrito de Rubia˜o Jr, CEP 18618-970, Botucatu, Sa˜o Paulo, Brazil.

Email:

rmartins@fmb.unesp.br

Reprinted by permission of Otolaryngol Head Neck Surg. 2015; 152(2):302-307.